While seeking the source of interference on channel 11 in your 802.11n WLAN running within 2.4 GHz, you notice a signal in the spectrum analyzer real time FFT display. The signal is characterized with the greatest strength utilizing only 1-2 megahertz of bandwidth and it does not use significantly more bandwidth until it has weakened by roughly 20 dB. At approximately -70 dB, it spreads across as much as 35 megahertz of bandwidth.

What kind of signal is described?